Seki Kousuke, Komatsu Kenji, Tanaka Keisuke, Hiraga Masahiro, Kajiya-Kanegae Hiromi, Matsumura Hideo, Uno Yuichi
Nagano Vegetable and Ornamental Crops Experiment Station, Tokoo 1066-1, Souga, Shiojiri, Nagano, 399-6461 Japan.
2Department of Bioresource Development, Tokyo University of Agriculture, Funako, 1737, Atsugi, Kanagawa, 243-0034 Japan.
Hortic Res. 2020 Feb 1;7:15. doi: 10.1038/s41438-020-0241-4. eCollection 2020.
To improve several agronomic traits in crisphead lettuce ( L.) under high-temperature growth conditions, we investigated the correlation among those traits in multiple cultivars and performed genetic mapping of their causal genes. In a field cultivation test of Empire type (serrated leaf) and Salinas type (wavy leaf) cultivars, Empire type cultivars showed increased tipburn susceptibility and late bolting compared with Salinas type cultivars. We attempted genetic mapping of leaf shape and bolting time by ddRAD-seq using the F population derived from a cross between 'VI185' (Empire type) and 'ShinanoGreen' (Salinas type). These analyses suggested that both traits are controlled by a single locus in LG5. Genotyping of 51 commercial lettuce cultivars with a tightly linked marker () at this locus showed an association between its genotype and the serrated leaf phenotype. By further fine mapping and transcriptome analysis, a gene encoding putative CIN-like TCP transcription factor was determined to be a candidate gene at this locus and was designated as . An insertion of retrotransposable element was found in the allele of 'VI185', and its transcript level in the leaves was lower than that in 'ShinanoGreen'. Because shapes of leaf epidermal cells in 'VI185' were similar to those in the TCP family mutant of , the leaf shape phenotype was likely caused by reduced expression of . Furthermore, because it is known that the TCP family protein also controls flowering time via interaction with FT in , it was highly possible that gave pleiotropic effects on both leaf shape and bolting time in lettuce.
为了在高温生长条件下改善结球生菜的几个农艺性状，我们研究了多个品种中这些性状之间的相关性，并对其因果基因进行了遗传定位。在帝国类型（锯齿叶）和萨利纳斯类型（波浪叶）品种的田间栽培试验中，与萨利纳斯类型品种相比，帝国类型品种表现出更高的顶烧敏感性和抽薹延迟。我们尝试通过ddRAD-seq对叶形和抽薹时间进行遗传定位，使用从“VI185”（帝国类型）和“信浓绿”（萨利纳斯类型）杂交产生的F群体。这些分析表明，这两个性状均由LG5中的一个位点控制。用该位点紧密连锁的标记对51个商业生菜品种进行基因分型，结果表明其基因型与锯齿叶表型之间存在关联。通过进一步的精细定位和转录组分析，确定一个编码假定的CIN样TCP转录因子的基因是该位点的候选基因，并将其命名为。在“VI185”的等位基因中发现了反转录转座子的插入，其在叶片中的转录水平低于“信浓绿”。由于“VI185”中叶表皮细胞的形状与的TCP家族突变体中的相似，叶形表型可能是由于表达降低所致。此外，由于已知TCP家族蛋白也通过与中的FT相互作用来控制开花时间，因此极有可能对生菜的叶形和抽薹时间产生多效性影响。
